Presently, an apparatus that deposits thin films and an apparatus that modifies the surfaces of thin films exist as vacuum processing apparatuses. Among these apparatuses, a microwave plasma processing apparatus including a dielectric-covered line connected to a microwave transmission waveguide and a closed reaction vessel positioned below the dielectric-covered line and incorporating a sample table is known as a CVD apparatus, and is proposed in, for example, patent reference 1. In this microwave plasma processing apparatus, a plurality of gas supply portions are connected to the interior of the closed reaction vessel and communicate with each other via a buffer chamber formed in the upper side portion in the closed reaction vessel, and gas dispersion nozzles forming the gas supply portions are arranged throughout the entire periphery of the buffer chamber. Also, a gas supplied to the buffer chamber is supplied from a shower head covering the whole upper surface of the sample table.
In this apparatus, the gas supplied from the gas supply portions enters the buffer chamber in a dispersed state, and guided to a central portion of the closed reaction vessel after being further dispersed in the buffer chamber. Accordingly, the gas exists in a uniformly dispersed state in the closed reaction vessel, and this makes it possible to uniformly generate a microwave plasma.
Patent reference 1: Japanese Patent Laid-Open No. 5-55150